CN102326226B - Automatically the silk-screen printing technique adjusted - Google Patents

Abstract

The embodiment of the present invention is commonly provided in the apparatus and method of screen printed pattern on substrate.In one embodiment, patterned layer is printed on the surface of substrate together with multiple alignment marks.Measure these alignment marks position relative to the feature structure of substrate, to judge the physical location of patterned layer.Physical location is made comparisons with desired location the site error of the arrangement judging patterned layer on substrate.Use this information to adjust patterned layer arrangement on follow-up multiple treated substrates.

Description

Self-adjusting screen printing process

technical field

Embodiments of the invention generally relate to systems and processes for screen printing multi-layer patterns on the surface of a substrate.

Background technique

Solar cells are photovoltaic (PV) devices that directly convert sunlight into electrical power. Solar cells typically have one or more p-n junctions. Each p-n junction within semiconductor material includes two distinct regions, one side of which is designated as a p-type region and the other side as an n-type region. When the p-n junction of a solar cell is exposed to sunlight (consisting of energy from photons), the sunlight is directly converted into electricity via the photovoltaic (PV) effect. Solar cells generate a specific amount of electrical power and are laid out in modules sized to deliver the desired amount of system power. Solar modules use specific frames and connectors to attach to panels. Solar cells are typically formed on silicon substrates, which may be monocrystalline silicon substrates or polycrystalline silicon substrates. A typical solar cell includes a silicon wafer, silicon substrate, or silicon plate, usually less than about 0.3 mm in thickness, having an n -type silicon thin layer.

Over the past decade, the photovoltaic (PV) market has experienced an annual growth rate of over 30%. Some articles believe that the world's solar cell power production may exceed 10GWp in the future. It is estimated that more than 95% of all solar modules will be based on silicon wafers. High market growth rates and the need to significantly reduce the cost of solar electricity have created several serious challenges to inexpensively forming high quality solar cells. Therefore, a major part of fabricating solar cells lies in reducing the production costs required to form solar cells by improving device yield and increasing substrate yield.

Screen printing has long been used to print designs on objects such as cloth or ceramics, and in the electronics industry to print electrical component designs such as electrical contacts or interconnects on the surface of a substrate. State-of-the-art solar cell manufacturing processes also use screen printing processes. Misalignment of the screen printed pattern on the substrate surface due to positioning errors of the substrate on the automated conveyor, defects on the substrate edge, can lead to poor device performance and thus device yield issues. Manual calibration of substrate positioning within the system is time consuming and requires frequent adjustments based on differences between batches of substrates or shifts in the calibrated positions of the substrates.

Therefore, there is a need for a screen printing apparatus for producing solar cells, circuits, or other useful devices that has the advantages of controlling device positioning within the system, increased yield, and lower cost of ownership compared to other known apparatus Improved method.

Contents of the invention

The present invention generally provides an automated deposition process comprising the steps of: positioning a first substrate on a substrate support, wherein the first substrate has at least one feature; depositing a layer of material in a pattern onto the first substrate on the surface, wherein the pattern includes at least two alignment marks; using a system controller to determine the actual orientation and position of the at least two alignment marks relative to at least one feature of the first substrate; The information received during the actual orientation and actual position of the at least two alignment marks deposits a layer of material in a pattern at an adjusted orientation or an adjusted position relative to at least one feature of the second substrate onto the surface of a second substrate, wherein the orientation or position of the material deposited on the second substrate is closer to the intended orientation or position than the orientation or position of the material deposited on the first substrate.

Embodiments of the present invention may further provide an automated deposition process comprising the steps of: positioning a first substrate on a substrate support, wherein the first substrate has at least one feature; analyzing the substrate support using a system controller orientation and position of the first substrate on the first substrate; depositing a layer of material onto the surface of the first substrate in a pattern, wherein the pattern includes at least two alignment marks and is used by the system controller in analyzing the orientation and position of the substrate data received during positioning to align with at least one feature of the first substrate; determine the actual orientation and actual position of the deposited layer on the first substrate using the system controller; calculate the actual orientation and actual position of the deposited material layer a deviation between the position and the expected orientation and expected position; and using the calculated deviation to deposit a layer of material onto the second substrate in a pattern such that the orientation or position of the material deposited on the second substrate is greater than that deposited on The orientation or position of the material on the first substrate is closer to the intended orientation or position.

Embodiments of the present invention further provide an automated deposition process comprising the steps of: positioning a first substrate disposed on a substrate support at a first position, wherein the first substrate has at least one feature; using optical detection The system and system controller analyze the orientation and position of a first substrate positioned on a substrate support at a first location; deposit a layer of material in a pattern onto the first substrate on a substrate support positioned at a second location; On the surface of the substrate, the pattern includes at least two alignment marks and is aligned to at least one feature of the first substrate using data received by the system controller during analysis of the orientation and position of the first substrate ; positioning the first substrate and the substrate support at a first position; determining the actual orientation and actual position of the deposited layer on the first substrate positioned at the first position using the optical detection system and the system controller; calculating the deposition Deviations between the actual orientation and actual position of the material layer and the expected orientation and expected position; and using the calculated deviations to deposit the material layer in a pattern onto a second substrate held on the substrate support Arranged in the second position such that the orientation or position of the material deposited on the second substrate is closer to the desired orientation or position than the orientation or position of the material deposited on the first substrate.

An embodiment of the present invention further provides an automated deposition process system, including: a rotary actuator with a substrate support disposed on the rotary actuator, and the rotary actuator can be positioned between the first position and the second position the input conveyor belt, the input conveyor belt is positioned to load the first substrate onto the substrate support in the first position; the screen printing chamber has an adjustable silk screen disposed in the screen printing chamber A screen printing device, the screen printing chamber is positioned to print a pattern onto the first substrate when the substrate support is in the second position; the optical detection assembly has a camera and a lamp, and the optical detection assembly is positioned to act as the substrate support capturing a plurality of optical images of the first patterned layer when the bottom support is in the first position; and a system controller comprising software configured to determine an actual position of the alignment marks captured in the optical images of the first patterned layer Deviations from the expected positions of these alignment marks and adjusting the screen printing apparatus to account for the determined deviations prior to printing the second pattern layer on the second substrate.

Brief description of the drawings

So that the manner in which the above recited features of the invention can be understood in greater detail, a more particular description of the invention, summarized above, may be had by reference to various embodiments, some of which are shown in the accompanying drawings. It should be noted that the accompanying drawings only disclose specific embodiments of the invention and are not intended to limit the spirit and scope of the invention, since the invention may admit to other equivalent embodiments.

Figure 1A is a schematic isometric view of a system that may be used in conjunction with embodiments of the present invention to form multiple layers of desired patterns.

Figure IB is a schematic plan view of the system in Figure IA.

Fig. 2 is a plan view of the front surface, ie, the light-receiving surface, of a solar cell substrate.

FIG. 3A illustrates multiple exemplary examples of a plurality of alignment marks printed on a substrate according to one embodiment of the present invention.

3B-3D illustrate various configurations of multiple alignment marks on the front surface of a substrate according to embodiments of the present invention.

4A is a schematic isometric view of an embodiment of a rotary actuator assembly illustrating a configuration in which the detection assembly is positioned to detect the front surface of a substrate.

Figure 4B illustrates an embodiment of a rotary actuator for controlling the illumination of the front surface of a substrate.

5 is a schematic isometric view of one embodiment of a rotary actuator assembly in which the detection assembly includes a plurality of optical detection devices.

FIG. 6 is a schematic illustration of an operational sequence for accurately screen printing a two-layer pattern on the front surface of a substrate 150 according to an embodiment of the present invention.

7 is a top plan view of a system that may be used in conjunction with embodiments of the present invention to form multiple layers of desired patterns.

To facilitate understanding, the same reference numerals in the various drawings represent similar components as far as possible. It should be understood that elements and/or process steps of one embodiment may be incorporated into other embodiments without further detail herein.

It should be noted that the accompanying drawings only disclose specific embodiments of the invention and are not intended to limit the spirit and scope of the invention, since the invention may allow other equivalent embodiments.

detailed description

Embodiments of the present invention provide an apparatus and method for processing multiple substrates in a screen printing system that utilizes improved substrate handling, alignment, and screen printing processes to improve substrate The device yield performance and cost-of-ownership (CoO) of the bottom processing line. In one embodiment, a screen printing system (hereinafter referred to as the system) is adapted to perform a screen printing process in a crystalline silicon solar cell production line in which a substrate is patterned with a desired material in two or more layers, and The substrate is then processed in one or more subsequent process chambers. The subsequent processing chamber may be adapted to perform one or more baking steps and one or more cleaning steps. In one embodiment, the system is a module located in a Softline™ tool available from Baccini S.p.A., owned by Applied Materials, Inc. of Santa Clara, California, USA. Although the following description primarily discusses the process of screen printing a pattern (eg, interconnect or contact structure) on the surface of a solar cell device, this configuration is not intended to limit the scope of the invention to what is described herein.

1A is a schematic isometric view and FIG. 1B is a schematic plan view. FIGS. 1A and 1B illustrate one embodiment of a screen printing system, system 100, that may be used in conjunction with embodiments of the present invention to print solar cell substrates. A desired pattern is formed on the surface of 150 . In one embodiment, the system 100 includes an incoming conveyor 111 , a rotary actuator assembly 130 , a screen printing chamber 102 , and an outgoing conveyor 112 . Incoming conveyor 111 may be configured to receive substrate 150 from an input device (e.g., input conveyor 113) and transfer substrate 150 to printing nest 131, which is coupled to The actuator assembly 130 is rotated. The output conveyor 112 may be configured to receive a processed substrate 150 from the printing nest 131 coupled to the rotary actuator assembly 130 and to transfer the substrate 150 to a substrate removal device (eg, the exit conveyor 114 ). . The input conveyor 113 and the exit conveyor 114 may be automated substrate handling equipment that is part of a large scale production line. For example, the input conveyor 113 and the exit conveyor 114 can be part of a Softline™ tool in which the system 100 can be a module.

In one configuration, as shown in FIG. 5 , each printing nest 131 is generally comprised of a conveyor assembly having a feed spool 135, a take-up spool (not shown), and one or more actuators ( not shown), wherein the actuators are coupled to the feed reel and/or take-up reel and are adapted to feed and maintain the support material 137 positioned across the platform 138. Platform 138 generally has a substrate support surface on which substrate 150 and support material 137 are positioned during the performance of the screen printing process within screen printing chamber 102 . In one embodiment, the support material 137 is a porous material that allows the substrate 150 disposed on one side of the support material 137 to be vacuumed by conventional vacuum generating devices (e.g., vacuum pumps, vacuum ejectors). Vacuum is maintained on platform 138 by applying a vacuum to the opposite side of support material 137 . In one embodiment, a vacuum is applied to a plurality of vacuum ports (not shown) formed in the substrate support surface 138A of the platform 138 so that the substrate can be "suctioned" onto the substrate support surface 138A of the platform. In one embodiment, the support material 137 is a transpirable material made of, for example, transpirable paper of the type used in cigarettes or other similar material such as plastic or textile material that can perform the same function. ) constitutes. An example of an exemplary printed nesting design is further described in co-pending US Patent Application No. 12/257,159 [Attorney Docket No. 13565], filed October 23, 2008.

As shown in FIG. 1A , the rotary actuator assembly 130 can be rotated and angularly positioned about the “B” axis by the rotary actuator (not shown) and the system controller 101 so that the printing nest 131 can be positioned in the system 100 Optionally angled inside. Rotary actuator assembly 130 may also have one or more support members to facilitate control of print nest 131 or other automated equipment used to execute substrate processing sequences in system 100 .

In one embodiment, the rotary actuator assembly 130 includes four printing nests 131, or substrate supports, each adapted to support a substrate during a screen printing process performed within the screen printing chamber 102. 150. Figure 1B schematically illustrates the position of the rotary actuator assembly 130, in which a printing nest 131A is at position "1" receiving a substrate 150 from an input conveyor 131 and another printing nest 131B is located in the screen printing chamber 102 in position "2" so that another substrate 150 can receive a screen printed pattern on the surface of the substrate 150, another printing nest 131C is in position "3" for delivering the processed substrate 150 to the output conveyor belt 112, and another printing nest 131D is located at position "4", which is an intermediate stage between position "1" and position "3".

In one embodiment, the screen printing chamber 102 within the system 100 uses a plurality of conventional screen printing heads available from Baccini S.p.A. which are adapted to print on the surface of the substrate 150 during the screen printing process. The material is deposited in the desired pattern on the substrate 150 positioned in the print nest 131 at position "2". In one embodiment, the screen printing chamber 102 contains a plurality of actuators, such as those of the screen printing mask that can communicate with the system controller 101 and can be adjusted to the substrate via commands from the system controller 101. Positional and/or angular orientation of the actuator 102A (eg, stepper motor, servo motor). In one embodiment, the screen printing chamber 102 is adapted to deposit metal-containing or dielectric-containing materials onto the solar cell substrate 150 . In one embodiment, the solar cell substrate 150 has a width between about 125 mm and about 156 mm and a length between about 70 mm and about 156 mm.

In one embodiment, the system 100 includes an inspection assembly 200 adapted to inspect the substrate 150 on the print nest 131 at position "1". The detection assembly 200 may include one or more cameras 121 positioned to detect an incoming processed substrate 150 on the print nest 131 at position "1". In one embodiment, the detection assembly 120 includes at least one camera 121 (eg, a CCD camera) and other electronic components that can detect and communicate the detection results to the system controller 101, which is used to analyze the The orientation and position of the substrate 150. In one embodiment, each of the printing nests 131 may contain a lamp 123 ( FIG. 4B ), or other similar optical radiation device, to illuminate the substrate 150 positioned on the printing nest 131 so that the inspection assembly 200 may be more easily The substrate 150 is detected.

In one embodiment, the system 100 may also include a second detection assembly 201 positioned to detect the substrate after material has been deposited on the surface of the substrate in the screen printing chamber 102 to analyze The location of the deposited layer on the substrate surface. In one configuration, as described above, the second detection component 201 is similar to the detection component 200 , and the second detection component can generally detect and communicate the detection result to the system controller 101 . In one example, the second inspection assembly 201 is adapted to inspect the substrate 150 on the printing nest 131 at position "3". Inspection assembly 201 may include one or more cameras 121 (eg, CCD cameras) positioned to inspect processed substrate 150 on print nest 131 at position "3".

System controller 101 facilitates control and automation of overall system 100 and may include a central processing unit (CPU) (not shown), memory (not shown), and support circuitry (or I/O) (not shown). The CPU can be one of any form of computer processor used in industrial installations that control various chamber processes and hardware (e.g., conveyor belts, detectors, motors, fluid transfer hardware, etc.), and monitor The system and chamber process (eg, substrate position, process time, detector signal, etc.). The memory is connected to the CPU and can be one or more of readily available memories such as random access memory (RAM), read only memory (ROM), floppy disks, hard disks, or any form of digital storage, whether local or remotely. Software instructions and data can be encoded and stored in the memory to instruct the CPU. Support circuitry may also be coupled to the CPU to support the processor in a conventional manner. Support circuits may also include cache memory, power supplies, clock circuits, input/output circuits, subsystems, and the like. Programs (or computer instructions) readable by the system controller 101 determine which tasks can be performed on the substrate. Preferably, the program is software that can be read by the system controller 101, and the program includes at least one piece of substrate position information for generating and storing, movement sequences of various controlled components, substrate detection system information, and for Generate and store at least one code of any combination of substrate position information, movement sequences of various controlled components, and substrate inspection system information. In an embodiment of the present invention, the system controller 101 includes pattern recognition software to resolve the positions of these alignment marks, as described later with reference to FIGS. 3A-3D . Pattern recognition software can also be used to correct for distortions or changes in the shape of the alignment marks, allowing more accurate data to be collected about the actual location of the screen printed pattern. In one embodiment, pattern recognition software is adapted to measure the distortion of the alignment marks relative to the expected state of the alignment marks by using the images received by the system controller 101 from the inspection assembly 200, and then use conventional geometric/mathematical techniques to Define the actual location of the alignment marks and the silkscreen pattern.

FIG. 2 is a plan view of the front surface 155 of the solar cell substrate 150 , that is, the light receiving surface. When the solar cell is illuminated, the current generated by the junction formed in the solar cell flows through the front contact structure 156 provided on the front surface 155 of the solar cell substrate 150 and the back surface (not shown) of the solar cell 150. out) backside contact structure (not shown). As shown in FIG. 2, the front contact structure 156 can be configured as a plurality of widely spaced thin metal lines or fingers (fingers) 152, which can supply current to the larger busbar (bus bar) 151. Generally, the front surface 155 is coated with a thin layer of dielectric material (eg, silicon nitride (SixNy)) that acts as an anti-reflective coating (ARC) to minimize light reflection. Because the back surface of the solar cell substrate 150 is not a light receiving surface, back contact structures (not shown) are generally not limited to thin metal lines.

In one embodiment, the placement of the bus bars 151 and fingers 152 on the front surface 155 of the substrate 150 depends on the relative print nesting of the screen-printed device used in the screen-print chamber 102 (FIG. 1A). Alignment of the positioning of the substrate 150 on 131 . A screen-printed device typically has a screen-printing mask contained within the screen-printing chamber 102, the screen-printing mask having a plurality of holes, slits, or other features formed inside to define the screen-printing pattern. Pattern and placement of ink or paste on front surface 155 of substrate 150 . In general, the alignment of the screen-printed pattern 153 of the fingers 152 and bus bars 151 on the surface of the substrate 150 depends on the features of the screen-printed device to the substrate 150 (eg, edge 150A, edge 150A, 150B) alignment and positioning. For example, the placement of a single layer screen printed pattern of bus bars 151 and fingers 152 may have a desired position X and desired angular orientation R relative to edge 150A, and a desired position Y relative to edge 150B of substrate 150 ,as shown in picture 2. The position error of the single layer screen printing pattern of fingers 152 and busbars 151 on the front surface 155 of the substrate 150 from the expected position (X, Y) and the expected angular orientation R on the front surface 155 of the substrate 150 It can be described as position deviation (ΔX, ΔY) and angle deviation (ΔR). Therefore, the positional deviation (ΔX, ΔY) is the error in the placement of the busbar 151 and finger 152 pattern relative to the edges 150A and 150B, and the angular deviation (ΔR) is the error in the printed pattern of the busbar 151 and finger 152 relative to the substrate. The error in the angular alignment of the edge 150B of the bottom 150. Misalignment of the single-layer screen-printed pattern of bus bars 151 and fingers 152 on front surface 155 of substrate 150 may affect the ability of formed devices to perform correctly and thus affect the device yield of system 100 .

In order to improve the accuracy of the alignment of the screen printing pattern with the edge or other features of the substrate, embodiments of the present invention utilize one or more optical detection devices, the system controller 101, and one or more alignment marks, wherein these align Alignment marks are formed on the front surface 155 of the substrate 150 during printing of the first layer of the screen printing pattern to automatically adjust the alignment of the screen printing pattern relative to the substrate. In general, by using the information received by the system controller 101 from one or more optical detection devices and the ability of the system controller 101 to control the position and orientation of the screen printing mask relative to the substrate surface, the The screen printing pattern 153 is aligned with the surface of the substrate. The screen printing mask is generally coupled to one or more mechanical actuators 102A (FIG. 1A) adapted to position and position the screen printing mask within the screen printing chamber 102 in an automated fashion. Align to desired position. In an embodiment, the optical detection device includes one or more components included in the detection device 200 . In one embodiment, the one or more alignment marks or fiducial marks may include alignment marks 160 shown below in FIGS. 3A-3D .

3A illustrates several examples of alignment marks 160, such as alignment marks 160A-160D, that may be formed on front surface 155 of substrate 150 during the screen printing process of bus bars 151 and fingers 152. , and the detection component 200 is used to find out the positional deviation (ΔX, ΔY) and angular deviation (ΔR) of the first layer bus bar 151 and the finger 152 screen-printed on the front surface 155 of the substrate 150 . In one embodiment, the alignment marks 160 are printed onto unused areas of the front surface 155 of the substrate 150 to prevent the alignment marks 160 from affecting the performance of the formed solar cell device. In one embodiment, the alignment mark 160 may have a circular shape (eg, alignment mark 160A), a rectangular shape (eg, alignment mark 160B), a cross shape (eg, alignment mark 160C), or an alphanumeric shape. (eg, alignment mark 160D). It is generally desirable to choose the shape of the marks 160 such that the pattern recognition software in the system controller 101 can accurately resolve the actual location of the alignment marks 160, and thus the front surface 155 of the substrate 150 from the image viewed by the inspection assembly 200. The actual positions of the screen printing patterns of the busbars 151 and fingers 152 on the top. The system controller 101 can then resolve the positional deviation (ΔX, ΔY) from the expected position (X, Y) and the angular deviation ΔR from the expected angular orientation R, and adjust the alignment of the screen printing mask in the screen printing device to Misalignment of bus bars 151 and fingers 152 on the substrate surface is minimized. Accordingly, since the position of each screen printing nest relative to the rotary actuator assembly 131, the incoming conveyor 111, and the screen printing chamber 102 can be varied, each screen positioned within the rotary actuator assembly 130 Alignment of the printing nest 131 and the various components of the screen printing chamber 102 will require separate adjustments. It is believed that by using discrete, desired-shaped alignment marks (eg, circles) positioned on opposite edges of the substrate, the orientation and position of the deposited layer can be resolved more precisely.

3B-3D illustrate various configurations of alignment marks 160 on the front surface 155 of the substrate 150 that can be used to improve the system controller 101's calculation of deviation measurements from images received by the inspection assembly 200. the accuracy. FIG. 3B illustrates a configuration in which two alignment marks 160 are placed near opposite corners on the front surface 155 of the substrate 150 . In this embodiment, by spreading the alignment marks 160 as far as possible, relative errors to features on the substrate 150 (eg, edge 150A or 150B) can be more accurately resolved. FIG. 3C illustrates another configuration in which three alignment marks 160 are printed on the front surface 155 of the substrate 150 near a plurality of corners to facilitate resolution of the first pattern of bus bars 151A and fingers 152A. layer deviation.

FIG. 3D illustrates another configuration in which three alignment marks 160 are printed at strategic locations across the front surface 155 of the substrate 150 . In this embodiment, two of the alignment marks 160 are positioned on a line parallel to the edge 150A, and the third alignment mark 160 is positioned at a distance perpendicular to the edge 150A. In this embodiment, pattern recognition software in system controller 101 generates vertical reference lines L1 and L2 to provide additional information about the position and orientation of first layer bus bar 151A and fingers 152A relative to substrate 150 .

In some cases, the deposited screen-printed pattern and alignment marks 160 tend to distort or change shape in one or more directions due to the mechanical process by which the screen-printed pattern is deposited. In one embodiment, it is desirable to position the individual alignment marks 160 on the surface of the substrate 150 such that changes in the shape of these alignment marks 160 minimally affect the positional deviation data collected by the pattern recognition software in the system controller 101. .

4A is a schematic isometric view of an embodiment of rotary actuator assembly 130 illustrating a configuration in which detection assembly 200 is positioned to detect front surface 155 of substrate 150 disposed on print nest 131 . In an embodiment, the camera 121 is positioned above the front surface 155 of the substrate 150 such that the viewing area 122 of the camera 121 can detect at least one area of the front surface 155 on the substrate 150 . In one embodiment, viewing region 122 is positioned to view one or more alignment marks 160 and features of substrate 150 (eg, substrate edge 150A) to provide system controller 101 with information about bus bars 151A and Information about the deviation of the first layer of the screen printing pattern of the fingers 152A. In one embodiment, observation region 122 is positioned to observe the plurality of features (eg, edges 150A and 150B) and one or more alignment marks 160 on substrate 150 to provide information about the alignment of plurality of alignment marks 160 with the ideal The coordinate information of the positional deviation of the position, and thus provide the positional deviation (ΔX, ΔY) and the angular deviation ΔR of the busbar 151 and the finger 152 on the front surface 155 of the substrate 150 .

FIG. 4B illustrates an embodiment of an optical inspection assembly 200 for controlling the illumination of the front surface 155 of the substrate 150 to improve the accuracy of the position information received by the camera 121 . In an embodiment, lights 123 may be oriented such that shadows 161 produced by light “D” projected from lights 123 being obscured by alignment marks 160 are minimized. Generally speaking, since the reflected light E includes at least the first component E1 reflected from the alignment mark 160 and the second component E2 reflected from the shadow area 161 , the shadow 161 can affect the measurement size of the alignment mark 160 . A shadow 161 having a width W2 may affect the ability of the camera 121 to distinguish between the real width W1 of the alignment mark 160 and the apparent width W1+W2 of the alignment mark 160 . Therefore, it is desirable to orient lamps 123 as close as possible to perpendicular (ie, 90 degrees) to front surface 155 of substrate 150 to minimize the size of shadow 161 . In one embodiment, the lights 123 are oriented at an angle F between about 80 degrees and about 100 degrees. In another embodiment, the lights 123 are oriented at an angle F of between about 85 degrees and about 95 degrees.

In one embodiment, it is also desirable to control the wavelength of the light delivered from lamp 123 to help improve the ability of optical detection assembly 200 to accurately resolve the position of alignment mark 160 on front surface 155 of substrate 150 . In one embodiment, the lamp 123 uses a red LED to illuminate the front surface 155 of the substrate 150 . When the bus bars 151 and fingers 152 are printed on a silicon nitride (SiN) anti-reflective coating (ARC) layer (the anti-reflective coating layer is usually formed on the front surface 155 of the solar cell substrate 150), the red LED lights are particularly effective. In an embodiment, it is desirable to position the viewing area 122 of the camera 121 on the alignment mark 160 printed in the area where the ARC is formed on the front surface 155 of the substrate 150 .

5 is a schematic isometric view of one embodiment of a rotary actuator assembly 130, in which detection assembly 200 includes a plurality of optical detection devices. In one embodiment, the inspection assembly 200 includes three cameras 121A, 121B, and 121C adapted to observe three different regions of the front surface 155 of the substrate 150 . In one embodiment, cameras 121A, 121B, and 121C are each positioned to view an area of front surface 155 of substrate 150 that includes printed alignment marks 160 . In this embodiment, the measurement accuracy of the placement of the first layer of bus bars 151 and fingers 152 can be improved due to the reduction in the size of each of the individual viewing areas 122A, 122B, and 122C and thus the increase in The resolution, or number of pixels per unit area, while still allowing the positions of the alignment marks 160 to be spread out as much as possible across the front surface 155 of the substrate 150 to allow the system controller 101 to better resolve any alignment errors. In one example, each camera 121A, 121B, and 121C is a three megapixel CCD camera positioned to view an area of about 352 mm ^{2 of the substrate, where the substrate has a surface area of about 24,650 mm 2 .} However, if one wanted to use a single camera to achieve the same optical resolution of all alignment marks, this single camera would have to be able to view the entire substrate surface and would require a 210 megapixel CCD camera which would be prohibitively expensive and/or does not exist.

FIG. 6 is a schematic illustration of a sequence of operations 600 for precisely screen printing a pattern on the front surface 155 of the substrate 150 in accordance with an embodiment of the present invention. The process discussed in sequence of operations 600 may thus be used to calibrate and precisely align various substrate support devices, such as screen printing nests 131 that will be used to support and position substrates in printing chamber 102 . The methods discussed herein may be used during initial setup of the system 100, during routine maintenance activities as a random quality test of the deposition process and/or as a method to correct for process deviations.

Referring to FIGS. 1B and 6 , in substrate loading operation 602 , a first substrate 150 is loaded onto printing nest 131A at position “ 1 ” of rotary actuator assembly 130 along path “A”. In one example, as shown in FIGS. 1A , 1B, and 5 , the support material 137 in the printing nest 131 is adapted to receive instructions from the incoming conveyor 111 in coordination with instructions sent by the system controller 101 . Substrate 150 with 116 .

Next, in a first alignment operation 603, the blank front surface 155 of the substrate 150 and/or one or more features (e.g., FIG. 4A or 5), and the system controller 101 uses the collected data to adjust the position of the screen printing mask based on the images to accurately print on the front surface 155 of the substrate 150 in subsequent operations. deposit the desired pattern. The position of the screen printed pattern is then based on the collected orientation and position information of the substrate 150 on the platform 138 received by the optical inspection assembly 200 .

In operation 604 , rotary actuator assembly 130 is rotated such that print nest 131A containing loaded substrate 150 is moved in a clockwise direction along path B1 to position “2” within print chamber 102 .

In operation 606 , a first layer of screen printing pattern (eg, bus bars 151 , fingers 152 and at least two alignment marks 160 ) is printed on the front surface 155 of the substrate 150 . In one embodiment, three or more alignment marks 160 are printed on the front surface 155 of the substrate 150 . In one embodiment, the second substrate 150 is loaded onto the print nest 131B that is currently at position "1". In this embodiment, the second substrate 150 follows the same path as the first loaded substrate 150 through the entire sequence of operations.

In operation 607 , the rotary actuator assembly 130 is rotated to position the printing nest 131A at position “1” so that the screen printing pattern on the substrate can be analyzed by the optical inspection assembly 200 . In one embodiment, operation 607 includes a series of operations 608-612 to reposition print nest 131A at position "1". In this embodiment, operation 607 includes a series of additional operations 608-610 for loading substrates into respective printing nests 131C-131D attached to rotary actuator assembly 130, as discussed below. Although the process discussed in sequence of operations 600 generally discloses a rotary actuator assembly 130 having four printing nests 131, any number of substrate supports may be positioned without departing from the context as any number of substrate supports may be positioned by an automated assembly. Used within the basic scope of the invention described, this configuration is not intended to limit the number of printing nests.

In operation 608, the rotary actuator assembly 130 is rotated such that the print nest 131A containing the first load substrate 150 is moved in a clockwise direction along path B2 to position "3". In one embodiment, the printing nest 131B containing the second substrate 150 is moved to position “2” for printing the first layer of screen printing pattern on the second substrate 150 . In one embodiment, the third substrate 150 is loaded onto the print nest 131C currently at position "1". In this embodiment, the third substrate 150 follows the same path as the second substrate 150 through the entire sequence of operations.

In operation 610, the rotary actuator assembly 130 is rotated such that the print nest 131A containing the first load substrate 150 is moved in a clockwise direction along path B3 to position "4". In one embodiment, print nest 131B containing second substrate 150 is moved to position "3". In one embodiment, the third loading substrate 150 is moved to position “2” for printing the first layer of screen printing pattern on the third loading substrate 150 . In one embodiment, the fourth substrate 150 is loaded onto the print nest 131D currently at position "1". In this embodiment, the fourth substrate 150 follows the same path as the third substrate 150 through the entire sequence of operations.

In step 612, the rotary actuator assembly 130 is rotated such that the print nest 131A containing the first load substrate 150 is moved back to position "1" along path B4 in a clockwise direction.

In operation 614, the alignment of the screen-printed pattern deposition layer is analyzed by the optical detection assembly 200 positioned adjacent to position "1". In an embodiment, the optical inspection device 200 captures images of at least two alignment marks 160 printed on the front surface 155 of the substrate 150 . These images can be analyzed by image recognition software in the system controller 101 . Subsequently, the system controller 101 calculates the position deviation (ΔX, ΔY) and the angle deviation ΔR according to the expected position (X, Y) and the expected angular orientation R of the screen printing pattern, and the expected position (X, Y) and The expected angular orientation R is stored in the system controller 101 by analyzing at least two alignment marks 160 relative to features of the substrate 150, such as one or more edges 150A-150D, or the corners forming these features. in the memory. The positional deviation (ΔX, ΔY) and angular deviation ΔR data can then be stored in the memory of the system controller 101 . The system controller 101 then uses the positional deviation (ΔX, ΔY) and angular deviation ΔR information derived from this analysis to adjust the position of the screen printing mask within the screen printing chamber 102 so that subsequent positioning within the printing nest The processed substrate on 131A will have a more precisely placed screen printed pattern.

Then, when these patterns are subsequently repositioned to position "1" (i.e., operation 616), the alignment of the screen-printed patterns deposited on the respective substrates positioned on the respective print nests 131B-131D ) are respectively analyzed by the optical detection component 200 (ie, operation 617). During operation 616, the rotary actuator assembly 130 is rotated such that the desired printing nest (e.g., reference numerals 131B-131D) is rotated back to position "1" such that the liner positioned on the desired screen printing nest The deposited layer on the bottom can be detected by the optical detection unit 200 . During each operation 617, the same or similar processes performed on each substrate positioned on the print nests 131B-131D are the same as or similar to operation 614 described above. The positional deviation (ΔX, ΔY) and angular deviation ΔR data collected for each printing nest 131A- 131D are thus stored in the memory of the system controller 101 for positioning subsequent substrates to be processed in each corresponding printing nest .

It will be appreciated by those skilled in the art that alignment operation 603 is used to correct for variations in the position of substrate 150 relative to stage 138 ( FIG. 5 ) in print nest 131 and that operations 614, 617 are used to correct The positional error of the printed pattern relative to the features of the substrate. Thus, while alignment operation 613 is typically used to print all substrates to be processed in chamber 102 to correct for variations in the position of substrate 150 on stage 138, operation 614 and/or operation 617 may occasionally be performed to correct or adjust over time. Variations in the placement of the screen-printed pattern relative to the substrate. As noted above, therefore, the methods described herein may be used during initial setup of the system 100 , during routine maintenance activities as a random quality test of the deposition process and/or as a method of correcting for process deviations. In one embodiment, the system controller 101 is configured to automatically analyze, at some desired interval, the orientation and position of the screen-printed pattern within a series, or sequence, of substrates to be processed, where the substrates are individually printed within the system 100. Nest 131 is processed on. In one arrangement, the system controller is adapted to use the latest orientation and position data collected from substrates positioned on the same screen printing nest to alter the substrate deposited on each subsequent to-be-processed substrate positioned on the same screen printing nest. Orientation and/or position of the screen printed pattern on the substrate. In one example, the system controller is adapted to analyze and readjust the orientation of every substrate, every other substrate, every third substrate, every tenth substrate, every hundred substrates, or other desired intervals Screen printing pattern.

In one embodiment, the optical detection assembly 200 is adapted to perform alignment operation 603 , and the second optical detection assembly 201 is adapted to perform operations 614 and 617 . In one embodiment, during operation 607 , the rotary actuator assembly 130 is rotated such that the printing nest is repositioned at position “3” so that the screen printing pattern on the substrate can be analyzed by the optical inspection assembly 201 . In this configuration, the orientation and position results received by the system controller 101 from the various detection assemblies 200, 201 may need to be calibrated or adjusted such that unwanted measurements produced by two differently positioned and aligned detection assemblies Errors do not affect the accuracy of the auto-alignment process results. In one example, it is desirable to minimize errors in orientation and position so that the placement of the patterned layer on the substrate can be less than about ±60 microns (m), and preferably less than about ±15 m.

Alternate system configuration

Although the embodiment of the present invention shows a system 100 with a single input and a single output in FIG. 1A and FIG. draw.

7 is a top plan view of a system 700 that may be used in conjunction with embodiments of the present invention to form desired patterns (eg, bus bars 151 and fingers 152 ) on front surface 155 of substrate 150 . As shown, the system 700 is different from the system 100 shown in FIGS. 1A and 1B , in that the system 700 includes two incoming conveyor belts 111 and two outgoing conveyor belts 112 . System 700 also differs from system 100 in that system 700 includes two screen printing chambers 102 . However, the operation sequence of the system 700 in the embodiment of the present invention is substantially the same as the operation sequence in the system 100 . For example, the sequence of operations 600 for the first substrate 150 is the same as previously described with reference to FIG. 6, initially loaded to position "1". However, the sequence of operations 600 may run concurrently to initially load the second substrate 150 to position "3".

While the foregoing has been described with respect to an embodiment of the invention, other and further embodiments may be devised without departing from the basic scope of the invention and its scope as defined by the appended claims.

Claims (21)

1. automatization's depositing operation, comprises the following steps:

Positioning the first substrate on substrate support, wherein said first substrate has at least one edge；

With a pattern by the surface of material layer depositions to described first substrate, wherein said pattern includes at least Two alignment marks；

System controller is used to determine that described at least two alignment mark is relative to described in described first substrate The actual orientation at least one edge and position, and it is inclined to calculate the position between physical location and desired location Angular deviation between difference and actual orientation and expection angular orientation；And

Use described position deviation and the information of described angular deviation, relative at least one of the second substrate In the adjusted orientation at edge or adjusted position, with a pattern by material layer depositions to described second substrate On surface, the orientation or the position ratio that are wherein deposited on the material on described second substrate are deposited on described first lining The orientation of the material at the end or position are closer to described expection orientation or described desired location.

2. automatization as claimed in claim 1 depositing operation, it is characterised in that described material includes a plurality of Conductive material line.

3. automatization as claimed in claim 2 depositing operation, it is characterised in that described substrate is polygon And each in described at least two labelling is printed on different corner regions.

4. automatization as claimed in claim 1 depositing operation, it is characterised in that determine described at least two The actual orientation of alignment mark and the step of position comprise the following steps: capture the optical picture of described alignment mark As and identify the physical characteristic of alignment mark on described optical imagery.

5. automatization as claimed in claim 4 depositing operation, it is characterised in that before printing ground floor, Expection orientation or the desired location of described alignment mark is determined relative at least one edge of described substrate.

6. automatization as claimed in claim 4 depositing operation, it is characterised in that at least three alignment mark It is printed on the surface of described substrate.

7. automatization as claimed in claim 6 depositing operation, it is characterised in that determine described at least two The actual orientation of alignment mark and the step of position comprise the following steps: two in described alignment mark right Build the first datum line between fiducial mark note, and between the 3rd alignment mark and described first datum line, build the Two datum lines, wherein said second datum line is vertical with described first datum line.

8. automatization's depositing operation, comprises the following steps:

Positioning the first substrate on substrate support, wherein said first substrate has at least one edge；

System controller is used to analyze orientation and the position of described first substrate on substrate support；

With pattern by the surface of material layer depositions to described first substrate, wherein said pattern includes at least two Individual alignment mark using is connect during analyzing the orientation of described substrate and position by described system controller The data received are directed at at least one edge of described first substrate making described pattern；

Described system controller is used to determine actual orientation and the physical location of sedimentary on described first substrate；

Calculate deposition material layer actual orientation and physical location and expection orientation and desired location between inclined Difference；And

Use the deviation calculated with pattern by material layer depositions to the second substrate, so that being deposited on described The orientation of the orientation of the material on the second substrate or the position material on described first substrate than being deposited on or position Put closer to described expection orientation or described desired location.

9. automatization as claimed in claim 8 depositing operation, it is characterised in that described material includes a plurality of Conductive material line.

10. automatization as claimed in claim 9 depositing operation, it is characterised in that described substrate is many Each in limit shape and described at least two labelling is printed on different corner regions.

11. automatization as claimed in claim 8 depositing operations, it is characterised in that described in determining at least The actual orientation of two alignment marks and the step of position comprise the following steps: capture the light of described alignment mark Learn image and identify the physical characteristic of alignment mark on described optical imagery.

12. automatization as claimed in claim 8 depositing operations, it is characterised in that at printing ground floor Before, expection orientation or the desired location of described alignment mark is determined relative at least one edge of substrate.

13. automatization as claimed in claim 8 depositing operations, it is characterised in that at least three is directed at Labelling is printed on the surface of described substrate.

14. automatization as claimed in claim 8 depositing operations, it is characterised in that described in determining at least The actual orientation of two alignment marks and the step of position comprise the following steps: two in described alignment mark The first datum line, and structure between the 3rd alignment mark and described first datum line is built between individual alignment mark Building the second datum line, wherein said second datum line is vertical with described first datum line.

15. 1 kinds of automatization's depositing operations, comprise the following steps:

The first substrate being arranged on substrate support is positioned at primary importance, wherein said first substrate tool There is at least one edge；

Use Systems for optical inspection and system controller analyzing and positioning at the substrate support of described primary importance On the orientation of described first substrate and position；

With a pattern by material layer depositions to being arranged at described the of the second position on described substrate support On the surface of one substrate, wherein said pattern includes that at least two alignment mark using is controlled by described system Device data received by during the orientation analyzing described first substrate and position are come and described first substrate At least one edge alignment；

Described first substrate and described substrate support are positioned at described primary importance；

Use Systems for optical inspection and system controller to determine and be positioned in described the first of described primary importance The actual orientation of the sedimentary on substrate and physical location；

Calculate deposition material layer actual orientation and physical location and expection orientation and desired location between inclined Difference；And

Using the deviation calculated with a pattern by material layer depositions to the second substrate, wherein said second serves as a contrast The end, is set in the second position on described substrate support, so that being deposited on described second substrate The orientation of the orientation of material or the position material on described first substrate than being deposited on or position are closer to described Expection orientation or described desired location.

16. automatization as claimed in claim 15 depositing operations, it is characterised in that farther include Following steps:

With pattern by material layer depositions at least one or more substrate, each in described substrate is by phase Continue and be arranged on described substrate support；

After at least one or more substrate described deposits material layer, with pattern by material layer depositions to volume On outer-lining bottom；

Described additional substrate and described substrate support are positioned at described primary importance；

Described Systems for optical inspection and described system controller is used to determine the sedimentary on described additional substrate Actual orientation and physical location, wherein said additional substrate is positioned in described primary importance；

Calculate deposition material layer actual orientation and physical location and expection orientation and desired location between inclined Difference；And

Use the deviation calculated with other patterns by material layer depositions to the second additional substrate, wherein said Second additional substrate is arranged in the described second position on described substrate support, so that being deposited on institute State orientation or position the taking than the material being deposited on described additional substrate of material on the second additional substrate To or position closer to described expection orientation or described desired location.

17. automatization as claimed in claim 16 depositing operations, it is characterised in that described substrate is Each in polygon and described at least two labelling is printed on different corner regions.

18. automatization as claimed in claim 15 depositing operations, it is characterised in that described in determining extremely Few actual orientation of two alignment marks and the step of position comprise the following steps: capture described alignment mark Optical imagery also identifies the physical characteristic of described alignment mark on described optical imagery.

19. automatization as claimed in claim 15 depositing operations, it is characterised in that in printing first Before Ceng, determine expection orientation or the expection of described alignment mark relative at least one edge of described substrate Position.

20. automatization as claimed in claim 15 depositing operations, it is characterised in that at least three pair Fiducial mark note is printed on the surface of described substrate.

21. automatization as claimed in claim 15 depositing operations, it is characterised in that described in determining extremely Few actual orientation of two alignment marks and the step of position comprise the following steps: in described alignment mark The first datum line is built between two alignment marks, and between the 3rd alignment mark and described first datum line Building the second datum line, wherein said second datum line is vertical with described first datum line.